One potential deciding factor in whether Michigan joins the calendar could be a desire to avoid putting it in competition with the street race in Detroit which was revived this year and attracted backing from Chevrolet.

Adding either to the calendar could recreate the triple crown of 500-mile races, along with Fontana and of course the Indianapolis 500.

This is all assuming the problem of pack racing can be controlled. No-one who saw the last race there will forget what happened to Dario Franchitti: